We all have stage stories, dealing with the unexpected challenge of a stage interruption. A seasoned professional knows to adapt, sometimes exploit, as in the case of this Josh Williams Band performance at the Doyle Lawson Bluegrass Festival in Denton, NC last year. His bluegrass quartet's rendition of Mordecai included as special "guest" performance, as you'll see around 1:30 in this 3:15 clip: